The present invention relates to emergency evacuation equipment for aircraft, in particular to inflatable aircraft evacuation slides.
The requirement for reliably evacuating airline passengers in the event of an emergency is well-known. A conventional method of quickly evacuating a large number of passengers from an aircraft is to provide multiple emergency exits, each of which is equipped with an inflatable evacuation slide. Door-mounted emergency evacuation slides are typically contained within an enclosure mounted to the interior surface of the aircraft exit door. Opening of the door in the “armed” position causes the slide to be pulled downward out of the enclosure into a position immediately outboard of and below the door exit opening. The evacuation slide is then rapidly inflated to form a structure sufficiently rigid to enable the airline passengers to escape. Over-wing evacuation slides are typically mounted outside the pressurized aircraft fuselage in a compartment located within the wing-to-fuselage fairing. If an over-wing exit is opened, a signal is generated that causes the over-wing evacuation slide inflation system to begin inflation. In response to the inflation pressure signal, pneumatic locks are released, which allow the evacuation slide compartment cover to fall away. The expanding evacuation slide then is forced out of the compartment either by the action of the slide itself inflating or in some cases by means of a separate ejection bag that inflates and forces the uninflated evacuation slide horizontally out of the storage compartment prior to the inflation thereof.
Fuselage mounted evacuation slides present special difficulties. As with door-mounted and over-wing-mounted evacuation slides, weight and storage volume are of great concern. The requirement that the evacuation slide be fuselage-mounted, however, imposes an additional constraint in that since the evacuation slide compartment intrudes into the pressure hull of the aircraft, the compartment opening must be minimized to avoid placing undue stress on the aircraft skin and supporting airframe. The minimum opening constraint, in turn, causes difficulty in the rapid deployment of the evacuation slide, which must be forced through this minimal opening without tearing on the surrounding aircraft skin.